package com.zhou;

import java.util.Scanner;

/**
 * T20
 *
 * @author zhouxianfeng
 * @date 2021-9-6
 */
public class T20 {
    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        while (scanner.hasNext()) {
            int start = scanner.nextInt();
            int num = scanner.nextInt();
            resolve(new Problem(start, num));
        }


    }

    public static void resolve(Problem problems) {
        double start = problems.start;
        double num = problems.num;
        double sum = start;
        for (int j = 1; j < num; j++) {
            start = Math.sqrt(start);
            sum += start;
        }
        System.out.printf("%.2f\n", sum);
    }

    public static class Problem {
        int start;
        int num;

        Problem(int start, int num) {
            this.start = start;
            this.num = num;
        }
    }
}
